Dothideomycetes families incertae sedis » Seynesiopeltidaceae

Seynesiopeltis

Seynesiopeltis F. Stevens & R.W. Ryan, in Stevens, Bulletin of the Bernice P. Bishop Museum, Honolulu, Hawaii 19: 69 (1925).

Index Fungorum number: IF 5020; Facesoffungi number: FoF 07910, 1 morphological species (Species Fungorum 2022), no molecular data available.

Foliar epiphytes on leaves, causing black spots, usually confluent in groups, forming black colonies. Sexual morph: Mycelium superficial, sparse, light, septate, olive-green. Thyriothecia solitary or gregarious, superficial, circular, shield-like, shallow, conical, dome-like, fattened, upper region, carbonaceous, unilocular, brown to black, basal layer poorly developed, lacking a distinct central ostiole. Upper wall comprising radiating arranged parallel cells, cells at margin branching. Hamathecium comprising 1–3 µm wide, comprising numerous, cellular, branched pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate, saccate, with a knoblike pedicel, and conspicuous ocular chamber (in Congo red). Ascospores irregularly 2–3-seriate, dark brown when mature, uniseptate, strongly constricted at septum, upper cells longer and wider, basal cell shorter and narrower with an acute base, with a thick, structured, hyaline, cell wall. Asexual morph: Unknown (adapted from Hyde et al. 2013).

 Type species: Seynesiopeltis tetraplasandrae F. Stevens & R.W. Ryan

Notes: Seynesiopeltis is characterised by solitary or gregarious, superficial, circular, shield-like thyriothecia, fissitunicate, saccate asci with a knob like pedicel and conspicuous ocular chamber (in Congo red) and 2–3-seriate, uniseptate, dark brown ascospores. The asexual morph is unknown. Stevens (1925) observed setae on the ascomata of Seynesiopeltis but Hyde et al. (2013) could not see this character as it may have been lost during storage. Müller and Arx (1962), Arx and Müller (1975) and Lumbsch and Huhndorf (2010) treated Seynesiopeltis in Microthyriaceae. Wu et al. (2011a) transferred Seynesiopeltis to Dothideomycetes genera incertae sedis as it was morphologically different form other genera in Dothideomycetes. Hyde et al. (2013) introduced a new family Seynesiopeltidaceae to accommodate Seynesiopeltis based on the unique brown ascospores with very thick structured walls, and asci with very thick walls and staining in Congo red. Seynesiopeltis resembles members of Dothidasteroma and Cocconia (Parmulariaceae) in having brown ascospores but differs in morphology of the asci (Inácio & Cannon 2008). Seynesiopeltis is a distinct and type genus of Seynesiopeltidaceae. Molecular data is lacking for Seynesiopeltis. Fresh collections with DNA sequence data are needed to confirm its correct systematic position.

 

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